| 0850 | Main bath level 8.3%. Temps still a bit warm: MC = 37 K, Tower = 39 K, Sorb = 16.7 K, Still = 27 K |
|---|---|
| 0851 | IVC pumping pressure 1.9e-6 mbar, valved-out pressure 1.2e-5 mbar. |
| 0852 | Mixture is still open to fridge lines since last night: G1/G2 = 651/588 mbar |
| 0900 | Close V13a (isolating remaining mixture in dump), start 1K Pot |
| 0910 | Fill LN trap dewar |
| 0950 | Commence LHe transfer (8.3%). |
| 1110 | Cease LHe transfer (91.5%). |
| 1250 | Fridge is cooling slowly, with pot running at around 2.2 K (large heat load) and mixture acting as thermal exchange from pot-still-MC. The MC and tower temperatures are decreasing at only about 1K per hour. The still is cooling more quickly at around 9 K/hour. |
| 1258 | Still = 11.7 K, MC = 33 K, Tower = 35 K |
| 1400 | Open V13A to let more mix into fridge, until G2 (dump) falls to about 500 mbar |
| 1434 | Open 1K Pot needle valve enough to increase P2 to greater than 600 mbar. This causes quicker cooling of still and reduction of pressure in fridge lines (on G1) |
| 1540 | 1K Pot pressure (P2) steadily falling too, now below 200 mbar |
| 1554 | Still at 4.96 K and falling at about 0.1K every 7 minutes. G1 at 304 mbar. Need to get well below 3 K to begin condensing 4He… liquid in the fridge may help cool the MC faster (currently just conduction from gas) |
| 1554 | MC = 29.8 K, Tower = 30.9 K. Both falling at about 1.3 K per hour. |
| 1625 | Open V13a to let more mix in, until dump pressure (G2) falls to 425 mbar, then close again |
| 1950 | open V13a until G2 falls to 300 mbar |
| 2000 | Still = 3.00 K and G1 = 247 mbar, so probably some 4He is condensing now. MC = 22.8 K |